This invention relates generally to ammunition, and, more particularly to a highly accurate military type jacketed projectile for use with pistols, revolvers, submachine guns, or other weapons utilizing ammunition of the general proportions of pistol ammunition.
Small arms form a major portion of the ever expanding weapon industry. The term small arms embraces not only hand and shoulder weapons but also machine guns and automatic weapons of all sizes up to about 20 mm in caliber. One specific class of small arms, pistols, revolvers, and submachine guns (machine pistols) is characterized by a type of ammunition generally referred to as pistol ammunition, and in military configuration with full metal jackets, is generally accepted as being inaccurate. Some types of wadcutter, semi-wadcutter and hollow point ammunition developed for target and sporting uses, are reasonably accurate, but they do not satisfy international laws of warefare which requires that the bullet remain intact and not significantly deform upon impact with the human body. This requirement is usually satisfied by encasing the projectile in a jacket of cupronickel, gilding metal, or gilding metal clad steel. It is these "full metal jacketed" or "full patch" projectiles or bullets to which this invention applies.
More specifically, ammunition for small arms is conventionally referred to as a round and is made up of a cartridge case which contains therein, although not limited to, a percussion primer, a charge of smokeless powder, and a projectile (more commonly referred to as a bullet). The cartridge case is generally utilized to assemble the primer, powder charge, and projectile in one weather proof unit, in order to support these elements in their relative positions in the chamber, and to provide obturation during firing by expanding against the wall of the chamber, thus preventing escape of the powder gases to the rear. The physical properties of the case must be such as to provide the necessary strength to withstand firing and extraction stresses. The front end of the case forms the seat for the projectile or bullet.
The reasons for the inaccuracy of small arms ammunition are not well understood. For example, the typical configuration of the projectile or bullet has an ogive (nose) of a long elipitcal shape blending smoothly into a short cylindrical body. The base of the body is hollowed out to bring the weight of the projectile down to the desired value while retaining the streamlined profile. The resultant center of gravity of the projectile is therefore well forward, commonly within the ogive. An example of such a projectile can be found in U.S. Pat. No. 2,172,054.
As far as the accuracy is concerned with respect to such projectile configurations, it is clearly unacceptable. For example, a typical ten-shot group at fifty yards range for the U.S. 9 millimeter M-1 ball round has an extreme spread of approximately 8 inches. Consequently, much need arises in the area of small arms ammunition to produce a projectile (or bullet) which is capable of providing highly accurate performance.